feat(script): replace followRedirects with maxRedirects http option

internal/sarin/scripthttp.go

@@ -11,9 +11,6 @@ import (
 	"go.aykhans.me/sarin/internal/types"
 )
 
-// scriptHTTPMaxRedirects is the redirect limit when followRedirects is set.
-const scriptHTTPMaxRedirects = 10
-
 // scriptHTTPDefaultTimeout is the default timeout for script requests, independent of -T.
 const scriptHTTPDefaultTimeout = 30 * time.Second
 
@@ -65,7 +62,7 @@ func newScriptHTTPClient(dialFunc fasthttp.DialFunc, defaultTimeout time.Duratio
 	}
 }
 
-// Do sends the request. With followRedirects the timeout applies to each hop.
+// Do sends the request. With maxRedirects the timeout applies to each hop.
 // It can return the following errors:
 //   - types.ScriptHTTPRequestError
 func (c *scriptHTTPClient) Do(r *script.HTTPRequest) (*script.HTTPResponse, error) {
@@ -116,8 +113,8 @@ func (c *scriptHTTPClient) Do(r *script.HTTPRequest) (*script.HTTPResponse, erro
 	}
 
 	req.SetTimeout(timeout)
-	if r.FollowRedirects {
+	if r.MaxRedirects > 0 {
-		err = client.DoRedirects(req, resp, scriptHTTPMaxRedirects)
+		err = client.DoRedirects(req, resp, r.MaxRedirects)
 	} else {
 		err = client.Do(req, resp)
 	}

internal/script/http.go

@@ -1,7 +1,9 @@
 package script
 
 import (
+	"math"
 	"net/http"
+	"strconv"
 	"strings"
 	"time"
 
@@ -18,7 +20,7 @@ type HTTPRequest struct {
 	Body         string
 	Timeout      time.Duration // zero means the doer's default timeout
 	Insecure     bool
-	FollowRedirects bool
+	MaxRedirects int
 }
 
 // HTTPResponse is the response returned to a script by the http.* functions.
@@ -70,7 +72,7 @@ const (
 	httpOptionBody         = "body"
 	httpOptionTimeout      = "timeout"
 	httpOptionInsecure     = "insecure"
-	httpOptionFollowRedirects = "followRedirects"
+	httpOptionMaxRedirects = "maxRedirects"
 )
 
 // httpBridge connects http to the doer. Calls only work while transform runs.
@@ -97,6 +99,19 @@ func (b *httpBridge) do(req *HTTPRequest) (*HTTPResponse, error) {
 	return b.doer.Do(req)
 }
 
+// parseHTTPMaxRedirects checks that the redirect limit is a non-negative whole number.
+// It can return the following errors:
+//   - types.ScriptHTTPOptionError
+func parseHTTPMaxRedirects(count float64) (int, error) {
+	if count < 0 || count != math.Trunc(count) {
+		return 0, types.NewScriptHTTPOptionError(
+			httpOptionMaxRedirects,
+			types.NewScriptTypeError("a whole number of 0 or more", strconv.FormatFloat(count, 'f', -1, 64)),
+		)
+	}
+	return int(count), nil
+}
+
 // parseHTTPTimeout parses a Go duration string such as "500ms" or "2s".
 // It can return the following errors:
 //   - types.ScriptHTTPOptionError

internal/script/js_http.go

@@ -100,16 +100,22 @@ func (e *JsEngine) parseHTTPOptions(opts *goja.Object, req *HTTPRequest) error {
 			if req.Timeout, err = parseHTTPTimeout(timeout); err != nil {
 				return err
 			}
-		case httpOptionInsecure, httpOptionFollowRedirects:
+		case httpOptionInsecure:
 			flag, ok := value.Export().(bool)
 			if !ok {
 				return types.NewScriptHTTPOptionError(name, types.NewScriptTypeError("boolean", jsTypeName(value)))
 			}
 
-			if name == httpOptionInsecure {
 			req.Insecure = flag
-			} else {
+		case httpOptionMaxRedirects:
-				req.FollowRedirects = flag
+			count, ok := numberValue(value)
+			if !ok {
+				return types.NewScriptHTTPOptionError(name, types.NewScriptTypeError("number", jsTypeName(value)))
+			}
+
+			var err error
+			if req.MaxRedirects, err = parseHTTPMaxRedirects(count); err != nil {
+				return err
 			}
 		default:
 			return types.NewScriptHTTPOptionError(name, types.ErrScriptHTTPUnknownOption)
@@ -190,3 +196,15 @@ func (e *JsEngine) throw(err error) {
 	}
 	panic(errorValue)
 }
+
+// numberValue reports whether value is a JavaScript number, and returns it.
+func numberValue(value goja.Value) (float64, bool) {
+	switch number := value.Export().(type) {
+	case int64:
+		return float64(number), true
+	case float64:
+		return number, true
+	default:
+		return 0, false
+	}
+}

internal/script/lua_http.go

@@ -92,17 +92,20 @@ func (e *LuaEngine) parseHTTPOptions(opts *lua.LTable, req *HTTPRequest) error {
 				return
 			}
 			req.Timeout, err = parseHTTPTimeout(string(timeout))
-		case httpOptionInsecure, httpOptionFollowRedirects:
+		case httpOptionInsecure:
 			flag, ok := v.(lua.LBool)
 			if !ok {
 				err = types.NewScriptHTTPOptionError(name, types.NewScriptTypeError("boolean", v.Type().String()))
 				return
 			}
-			if name == httpOptionInsecure {
 			req.Insecure = bool(flag)
-			} else {
+		case httpOptionMaxRedirects:
-				req.FollowRedirects = bool(flag)
+			count, ok := v.(lua.LNumber)
+			if !ok {
+				err = types.NewScriptHTTPOptionError(name, types.NewScriptTypeError("number", v.Type().String()))
+				return
 			}
+			req.MaxRedirects, err = parseHTTPMaxRedirects(float64(count))
 		default:
 			err = types.NewScriptHTTPOptionError(name, types.ErrScriptHTTPUnknownOption)
 		}